None of the Proggy fonts are as clean as Monaco, although Proggy Tiny 11 comes close.

lower-case “a” should be double-storey, so it doesn’t look anything like lower-case “o”

zero “0″ should be slashed

lower-case “l” should have a serif on the bottom like lower-case “t”, and not look like numeral “1″ or upper-case “I”.

upper-case “U” and “V” differ by at least 7 pixels

gentle curves rather than blocky rectangles, please

It’s disappointing that Monaco can get so much right and get lower-case “a” wrong. Still, if anyone wants to port neep alt to a format OS X and iTerm can handle (even if it’s only at 13pt semicondensed)… I tried once with fontforge but it was pretty broken.